Array cameras are used in a variety of applications, the most common being imaging with depth perception. Such depth perception may be used, for example, for generation of stereo imagery (three-dimensional imagery), for retrospective focusing of images on objects within a desired depth range, or for achieving an extended depth of field (achieving good focus over an extended depth range). In imaging with depth perception, images captured by an array camera, having two or more cameras viewing the same scene, provide information about the distance from the array camera to objects in the scene. Thus, whereas a conventional single camera generates two-dimensional images only, such array cameras generate three-dimensional information about the scene. An array camera with two individual cameras configured for imaging with depth perception is generally known as a stereo camera. However, larger arrays may in some cases provide additional benefits. Stereo cameras are used in cars in advanced driver assistance systems, wherein the stereo cameras monitor the distance to nearby objects and alert the driver if a collision is impending. Another common application is machine vision. For example, a robot used to pick and place objects may be assisted by a stereo camera that determines the three-dimensional position of an object, to be picked up by the robot, and provides this information to the robot. Gesture control is emerging as yet another application of imaging with depth perception.
For any given application, the array cameras must comply with requirements to both form factor and cost while also achieving the performance needed for the intended application. For example, the accuracy of the three-dimensional position data provided by a stereo camera relies on accurate registration of imaging objectives to respective image sensors. In addition, the image quality and hence the accuracy of information obtainable from the images may be compromised by crosstalk (light leakage) between individual cameras of the array camera, and it is therefore generally preferred to minimize such crosstalk. Wafer-level manufacturing has proven to be the most cost-effective manufacturing method for conventional single cameras having a small form factor.